Hello, syzbot found the following crash on: HEAD commit: 7ae77150 Merge tag 'powerpc-5.8-1' of git://git.kernel.org.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=13880e71100000 kernel config: https://syzkaller.appspot.com/x/.config?x=be4578b3f1083656 dashboard link: https://syzkaller.appspot.com/bug?extid=6bed2d543cf7e48b822b compiler: clang version 10.0.0 (https://github.com/llvm/llvm-project/ c2443155a0fb245c8f17f2c1c72b6ea391e86e81) Unfortunately, I don't have any reproducer for this crash yet. IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+6bed2d543cf7e48b822b@xxxxxxxxxxxxxxxxxxxxxxxxx RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000004 R13: 0000000000000404 R14: 00000000004c6c29 R15: 00007f0c04c4a6d4 ================================================================== BUG: KASAN: null-ptr-deref in atomic_fetch_sub include/asm-generic/atomic-instrumented.h:199 [inline] BUG: KASAN: null-ptr-deref in refcount_sub_and_test include/linux/refcount.h:266 [inline] BUG: KASAN: null-ptr-deref in refcount_dec_and_test include/linux/refcount.h:294 [inline] BUG: KASAN: null-ptr-deref in kref_put include/linux/kref.h:64 [inline] BUG: KASAN: null-ptr-deref in media_request_put drivers/media/mc/mc-request.c:81 [inline] BUG: KASAN: null-ptr-deref in media_request_close+0x4d/0x170 drivers/media/mc/mc-request.c:89 Write of size 4 at addr 0000000000000008 by task syz-executor.5/16136 CPU: 0 PID: 16136 Comm: syz-executor.5 Not tainted 5.7.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1e9/0x30e lib/dump_stack.c:118 __kasan_report mm/kasan/report.c:517 [inline] kasan_report+0x151/0x1d0 mm/kasan/report.c:530 check_memory_region_inline mm/kasan/generic.c:183 [inline] check_memory_region+0x2b5/0x2f0 mm/kasan/generic.c:192 atomic_fetch_sub include/asm-generic/atomic-instrumented.h:199 [inline] refcount_sub_and_test include/linux/refcount.h:266 [inline] refcount_dec_and_test include/linux/refcount.h:294 [inline] kref_put include/linux/kref.h:64 [inline] media_request_put drivers/media/mc/mc-request.c:81 [inline] media_request_close+0x4d/0x170 drivers/media/mc/mc-request.c:89 __fput+0x2ed/0x750 fs/file_table.c:281 task_work_run+0x147/0x1d0 kernel/task_work.c:123 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_usermode_loop arch/x86/entry/common.c:165 [inline] prepare_exit_to_usermode+0x48e/0x600 arch/x86/entry/common.c:196 entry_SYSCALL_64_after_hwframe+0x49/0xb3 RIP: 0033:0x45ca69 Code: 0d b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 db b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f0c04c49c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: fffffffffffffff4 RBX: 00000000004e9300 RCX: 000000000045ca69 RDX: 00000000200000c0 RSI: 0000000080047c05 RDI: 0000000000000003 RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000004 R13: 0000000000000404 R14: 00000000004c6c29 R15: 00007f0c04c4a6d4 ================================================================== --- This bug is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx. syzbot will keep track of this bug report. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
